Method for selectively aperturing a nonwoven web

ABSTRACT

The present invention provides a method for selectively aperturing a nonwoven web. A nonwoven web is weakened along a plurality of locations and then a tensioning force is applied to the nonwoven web causing the nonwoven web to rupture at the plurality of weakened location creating a plurality of apertures in the nonwoven web coincident with the weakened locations.

FIELD OF INVENTION

The present invention relates to apertured nonwoven webs and a method ofmaking the same. Apertured nonwoven webs are particularly well suitedfor use in disposable absorbent articles such as diapers, incontinencebriefs, training pants, feminine hygiene garments, and the like.

BACKGROUND OF THE INVENTION

Nonwoven webs formed by nonwoven extrusion processes such as, forexample, meltblowing processes and spunbonding processes may bemanufactured into products and components of products so inexpensivelythat the products could be viewed as disposable after only one or a fewuses. Representatives of such products include disposable absorbentarticles, such as diapers, incontinence briefs, training pants, femininehygiene garments, and the like.

Infants and other incontinent individuals wear disposable absorbentarticles such as diapers to receive and contain urine and other bodyexudates. Absorbent articles function both to contain the dischargedmaterials and to isolate these materials from the body of the wearer andfrom the wearer's garments and bed clothing. Disposable absorbentarticles having many different basic designs are known to the art.

A typical absorbent article includes a liquid pervious topsheet, aliquid impervious backsheet joined to the topsheet, and an absorbentcore positioned between the topsheet and the backsheet. Nonwoven websare often used as the topsheet because they are liquid pervious andprovide a skin friendly surface. However, in certain uses nonwoven websdo not function all that well as a topsheet as body exudates sometimeshang-up or get caught in the nonwoven web and thus, become trappedagainst the wearer's skin. One solution to the aforementioned problem isto provide apertures in the nonwoven web so that body exudates mayreadily penetrate through the nonwoven web and into the underlyingabsorbent core. Unfortunately, certain techniques used to form aperturednonwoven webs are either costly, create an undesirable harsh feelingagainst the wearer's skin, or are subject to tearing, particularly whenthe apertured nonwoven web is to be used as a topsheet on a disposableabsorbent article.

As used herein, the term "nonwoven web", refers to a web that has astructure of individual fibers or threads which are interaid, but not inany regular, repeating manner. Nonwoven webs have been, in the past,formed by a variety of processes, such as, for example, meltblowingprocesses, spunbonding processes and bonded carded web processes.

As used herein, the term "microfibers", refers to small diameter fibershaving an average diameter not greater than about 100 microns.

As used herein, the term "meltblown fibers", refers to fibers formed byextruding a molten thermoplastic material through a plurality of fine,usually circular, die capillaries as molten threads or filaments into ahigh velocity gas (e.g., air) stream which attenuates the filaments ofmolten thermoplastic material to reduce their diameter, which may be toa microfiber diameter. Thereafter, the meltblown fibers are carded bythe high velocity gas stream and are deposited on a collecting surfaceto form a web of randomly dispersed meltblown fibers.

As used herein, the term "spunbonded fibers", refers to small diameterfibers which are formed by extruding a molten thermoplastic material asfilaments from a plurality of fine, usually circular, capillaries of aspinneret with the diameter of the extruded filaments then being rapidlyreduced as by, for example, eductive drawing or other well-knownspunbonding mechanisms.

As used herein, the term "polymer" generally includes, but is notlimited to, hompolymers, copolymers, such as, for example, block, graft,random and alternating copolymers, terpolymers, etc., and blends andmodifications thereof. Furthermore, unless otherwise specificallylimited, the term "polymer" shall include all possible geometricalconfigurations of the material. These configurations include, but arenot limited to, isotactic, syndiaotactic and random symmetries.

As used herein, the term "elastic" refers to any material which, uponapplication of a biasing force, is stretchable, that is, elongatable, atleast about 60 percent (i.e., to a stretched, biased length, which is atleast about 160 percent of its relaxed unbiased length), and which, willrecover at least 55 percent of its elongation upon release of thestretching, elongation force. A hypothetical example would be a one (1)inch sample of a material which is elongatable to at least 1.60 inches,and which, upon being elongated to 1.60 inches and released, willrecover to a length of not more than 1.27 inches. Many elastic materialsmay be elongated by more than 60 percent (i.e., much more than 160percent of their relaxed length), for example, elongated 100 percent ormore, and many of these materials will recover to substantially theirinitial relaxed length, for example, to within 105 percent of theirinitial relaxed length, upon release of the stretch force.

As used herein, the term "nonelastic" refers to any material which doesnot fall within the definition of "elastic" above.

As used herein, the term "extensible" refers to any material which, uponapplication of a biasing force, is elongatable, at least about 50percent without experiencing catastrophic failure.

As used herein, the term "melt-stabilized" refers to portions of anonwoven web which have been subjected to localized heating and/orlocalized pressure to substantially consolidate the fibers of thenonwoven web into a stabilized film-like form.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a method forselectively aperturing a nonwoven web comprising the steps of:

providing a nonwoven web;

weakening the nonwoven web at a plurality of locations to create aplurality of weakened, melt-stabilized locations; and

applying a tensioning force to the nonwoven web to cause the nonwovenweb to rupture at the plurality of weakened, melt-stabilized locationscreating a plurality of apertures in the nonwoven web coincident withsaid weakened, melt-stabilized locations.

The nonwoven web may include bonded carded webs, spunbonded webs, ormeltblown webs. The meltblown web may include meltblown microfibers. Thenonwoven web may also have multiple layers such as, for example,multiple spunbonded layers and/or multiple meltblown layers. Thenonwoven material may be made of polymers such as, for example,polyolefins. Exemplary polyolefins include polypropylene, polyethylene,ethylene copolymers and propylene copolymers. The nonwoven web may be anelastic nonwoven web, a nonelastic nonwoven web or an extensiblenonwoven web.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as formingthe present invention, it is believed that the invention will be betterunderstood from the following description which is taken in conjunctionwith the accompanying drawings in which like designations are used todesignate substantially identical elements, and in which:

FIG. 1 is a plan view of a disposable diaper embodiment of the presentinvention having portions cut away to reveal underlying structure, theinner surface of the diaper is facing the viewer;

FIG. 2 is a schematic representation of an exemplary process forselectively aperturing a nonwoven web of the present invention;

FIG. 3 is an enlarged perspective illustration of a web weakeningarrangement of the present invention;

FIG. 4 is an enlarged perspective illustration of an incrementalstretching system of the present invention;

FIG. 5 is a schematic representation of another process for selectivelyaperturing a nonwoven web of the present invention;

FIG. 6 is an enlarged perspective illustration of another web weakeningarrangement of the present invention;

FIG. 7 is an enlarged plan view photograph of a nonwoven web prior tobeing weakened;

FIG. 8 is an enlarged plan view photograph of a nonwoven web of thepresent invention after the nonwoven web has been weakened at aplurality of locations; and

FIG. 9 is an enlarged plan view photograph of a nonwoven web of thepresent invention after tension has been applied to rupture the nonwovenweb at the weakened locations to create apertures in the nonwoven.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "absorbent article" refers to devices whichabsorb and contain body exudates, and, more specifically, refers todevices which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term "disposable" is used herein to describe absorbentarticles which are not intended to be laundered or otherwise restored orreused as an absorbent article (i.e., they are intended to be discardedafter a single use and, preferably, to be recycled, composted orotherwise disposed of in an environmentally compatible manner). A"unitary" absorbent article refers to absorbent articles which areformed of separate parts united together to form a coordinated entity sothat they do not require separate manipulative parts like a separateholder and liner. A preferred embodiment of an absorbent article of thepresent invention is the unitary disposable absorbent article, diaper20, shown in FIG. 1. As used herein, the term "diaper" refers to anabsorbent article generally worn by infants and incontinent persons thatis worn about the lower torso of the wearer. It should be understood,however, that the present invention is also applicable to otherabsorbent articles such as incontinence briefs, incontinenceundergarments, diaper holders and liners, feminine hygiene garments,training pants, and the like.

FIG. 1 is a plan view of the diaper 20 of the present invention in itsflat-out, uncontracted state (i.e., with elastic induced contractionpulled out) with portions of the structure being cut-away to moreclearly show the construction of the diaper 20 and with the portion ofthe diaper 20 which faces the wearer, the inner surface 40, facing theviewer. As shown in FIG. 1, the diaper 20 preferably comprises acontainment assembly 22 comprising a liquid pervious topsheet 24; aliquid impervious backsheet 26 joined to the topsheet; and an absorbentcore 28 positioned between the topsheet 24 and the backsheet 26. Thediaper preferably further comprises elasticized side panels 30;elasticized leg cuffs 32; elasticized waistbands 34; and a fasteningsystem 36 preferably comprising a pair of securement members 37 and alanding member, (not shown).

The diaper 20 is shown in FIG. 1 to have an inner surface 40 (facing theviewer in FIG. 1), an outer surface 42 opposed to the inner surface 40,a rear waist region 44, a front waist region 46 opposed to the rearwaist region 44, a crotch region 48 positioned between the rear waistregion 44 and the front waist region 46, and a periphery which isdefined by the outer perimeter or edges of the diaper 20 in which thelongitudinal edges are designated 50 and the end edges are designated52. The inner surface 40 of the diaper 20 comprises that portion of thediaper 20 which is positioned adjacent to the wearer's body during use(i.e., the inner surface 40 generally is formed by at least a portion ofthe topsheet 24 and other components joined to the topsheet 24). Theouter surface 42 comprises that portion of the diaper 20 which ispositioned away from the wearer's body (i.e., the outer surface 42 isgenerally formed by at least a portion of the backsheet 26 and othercomponents joined to the backsheet 26). As used herein, the term"joined" encompasses configurations whereby an element is directlysecured to the other element by affixing the element directly to theother element, and configurations whereby the element is indirectlysecured to the other element by affixing the element to intermediatemember(s) which in turn are affixed to the other element. The rear waistregion 44 and the front waist region 46 extend from the end edges 52 ofthe periphery to the crotch region 48.

The diaper 20 also has two centerlines, a longitudinal centerline 90 anda transverse centerline 92. The term "longitudinal", as used herein,refers to a line, axis, or direction in the plane of the diaper 20 thatis generally aligned with (e.g. approximately parallel with) a verticalplane which bisects a standing wearer into left and right halves whenthe diaper 20 is worn. The terms "transverse" and "lateral", as usedherein, are interchangeable and refer to a line, axis or direction whichlies within the plane of the diaper that is generally perpendicular tothe longitudinal direction (which divides the wearer into front and backbody halves).

The containment assembly 22 of the diaper 20 is shown in FIG. 1 ascomprising the main body (chassis) of the diaper 20. The containmentassembly 22 comprises at least topsheet 24, backsheet 26 and absorbentcore 28. When the absorbent article comprises a separate holder and aliner, the containment assembly 22 generally comprises the holder andthe liner (i.e., the containment assembly 22 comprises one or morelayers of material to define the holder while the liner comprises anabsorbent composite such as a topsheet, a backsheet, and an absorbentcore.) For unitary absorbent articles, the containment assembly 22comprises the main structure of the diaper with other features added toform the composite diaper structure. Thus, the containment assembly 22for the diaper 20 generally comprises the topsheet 24, the backsheet 26,and the absorbent core 28.

FIG. 1 shows a preferred embodiment of the containment assembly 22 inwhich the topsheet 24 and the backsheet 26 have length and widthdimensions generally larger than those of the absorbent core 28. Thetopsheet 24 and the backsheet 26 extend beyond the edges of theabsorbent core 28 to thereby form the periphery of the diaper 20. Whilethe topsheet 24, the backsheet 26, and the absorbent core 28 may beassembled in a variety of well known configurations, exemplarycontainment assembly configurations are described generally in U.S. Pat.No. 3,860,003 entitled "Contractible Side Portions for DisposableDiaper" which issued to Kenneth B. Buell on Jan. 14, 1975; and U.S. Pat.No. 5,151,092 entitled "Absorbent Article With Dynamic Elastic WaistFeature Having A Predisposed Resilient Flexural Hinge" which issued toKenneth B. Buell et al., on Sep. 29, 1992; each of which is incorporatedherein by reference.

The absorbent core 28 may be any absorbent member which is generallycompressible, conformable, non-irritating to the wearer's skin, andcapable of absorbing and retaining liquids such as urine and othercertain body exudates. As shown in FIG. 1, the absorbent core 28 has agarment-facing side, a body-facing side, a pair of side edges, and apair of waist edges. The absorbent core 28 may be manufactured in a widevariety of sizes and shapes (e.g., rectangular, hourglass, "T"-shaped,asymmetric, etc.) and from a wide variety of liquid-absorbent materialscommonly used in disposable diapers and other absorbent articles such ascomminuted wood pulp which is generally referred to as airfelt. Examplesof other suitable absorbent materials include creped cellulose wadding;meltblown polymers including coform; chemically stiffened, modified orcross-linked cellulosic fibers; tissue including tissue wraps and tissuelaminates; absorbent foams; absorbent sponges; superabsorbent polymers;absorbent gelling materials; or any equivalent material or combinationsof materials.

The configuration and construction of the absorbent core 28 may vary(e.g., the absorbent core may have varying caliper zones, a hydrophilicgradient, a superabsorbent gradient, or lower average density and loweraverage basis weight acquisition zones; or may comprise one or morelayers or structures). Further, the size and absorbent capacity of theabsorbent core 28 may also be varied to accommodate wearers ranging frominfants through adults. However, the total absorbent capacity of theabsorbent core 28 should be compatible with the design loading and theintended use of the diaper 20.

One embodiment of the diaper 20 has an asymmetric, modified T-shapedabsorbent core 28 having ears in the front waist region but a generallyrectangular shape in the rear waist region. Exemplary absorbentstructures for use as the absorbent core 28 of the present inventionthat have achieved wide acceptance and commercial success are describedin U.S. Pat. No. 4,610,678 entitled "High-Density Absorbent Structures"issued to Weisman et al. on Sep. 9, 1986; U.S. Pat. No. 4,673,402entitled "Absorbent Articles With Dual-Layered Cores" issued to Weismanet al. on Jun. 16, 1987; U.S. Pat. No. 4,888,231 entitled "AbsorbentCore Having A Dusting Layer" issued to Angstadt on Dec. 19, 1989; andU.S. Pat. No. 4,834,735, entitled "High Density Absorbent Members HavingLower Density and Lower Basis Weight Acquisition Zones", issued toAlemany et al. on May 30, 1989. The absorbent core may further comprisethe dual core system containing an acquisition/distribution core ofchemically stiffened fibers positioned over an absorbent storage core asdetailed in U.S. Pat. No. 5,234,423, entitled "Absorbent Article WithElastic Waist Feature and Enhanced Absorbency" issued to Alemany et al.,on Aug. 10, 1993; and in U.S. Pat. No. 5,147,345, entitled "HighEfficiency Absorbent Articles For Incontinence Management" issued toYoung, LaVon and Taylor on Sep. 15, 1992. All of these patents areincorporated herein by reference.

The backsheet 26 is positioned adjacent the garment-facing surface ofthe absorbent core 28 and is preferably joined thereto by attachmentmeans (not shown) such as those well known in the art. For example, thebacksheet 26 may be secured to the absorbent core 28 by a uniformcontinuous layer of adhesive, a patterned layer of adhesive, or an arrayof separate lines, spirals, or spots of adhesive. Adhesives which havebeen found to be satisfactory are manufactured by H. B. Fuller Companyof St. Paul, Minn. and marketed as HL-1258. An example of a suitableattachment means comprising an open pattern network of filaments ofadhesive is disclosed in U.S. Pat. No. 4,573,986 entitled "DisposableWaste-Containment Garment", which issued to Minetola et al. on Mar. 4,1986. Another suitable attachment means comprising several lines ofadhesive filaments swirled into a spiral pattern is illustrated by theapparatus and methods shown in U.S. Pat. No. 3,911,173 issued toSprague, Jr. on Oct. 7, 1975; U.S. Pat. No. 4,785,996 issued to Ziecker,et al. on Nov. 22, 1978; and U.S. Pat. No. 4,842,666 issued to Wereniczon Jun. 27, 1989. Each of these patents are incorporated herein byreference. Alternatively, the attachment means may comprise heat bonds,pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or any othersuitable attachment means or combinations of these attachment means asare known in the art. Embodiments of the present invention are alsocontemplated wherein the absorbent core is not joined to the backsheet26, the topsheet 24, or both in order to provide greater extensibilityin the front waist region 46 and the rear waist region 44.

The backsheet 26 is impervious to liquids (e.g., urine) and ispreferably manufactured from a thin plastic film, although otherflexible liquid impervious materials may also be used. As used herein,the term "flexible" refers to materials which are compliant and willreadily conform to the general shape and contours of the human body. Thebacksheet 26 prevents the exudates absorbed and contained in theabsorbent core 28 from wetting articles which contact the diaper 20 suchas bedsheets and undergarments, however, the backsheet 26 may permitvapors to escape from the absorbent core 28 (i.e., is breathable). Thus,the backsheet 26 preferably comprises a polymeric film such asthermoplastic films of polyethylene or polypropylene. A suitablematerial for the backsheet 26 is a thermoplastic film having a thicknessof from about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils).

The topsheet 24 is positioned adjacent the body-facing surface of theabsorbent core 28 and is preferably joined thereto and to the backsheet26 by attachment means (not shown) such as those well known in the art.Suitable attachment means are described with respect to joining thebacksheet 26 to the absorbent core 28. In a preferred embodiment of thepresent invention, the topsheet 24 and the backsheet 26 are joineddirectly to each other in the diaper periphery and are indirectly joinedtogether by directly joining them to the absorbent core 28 by theattachment means (not shown).

The topsheet 24 is preferably compliant, soft feeling, andnon-irritating to the wearer's skin. Further, the topsheet 24 ispreferably liquid pervious permitting liquids (e.g., urine) to readilypenetrate through its thickness. A suitable topsheet 24 is manufacturedfrom a nonwoven web of synthetic fibers (e.g., polyester, polyethylene,or polypropylene fibers or bicomponent fibers). Other suitable fibersinclude natural fibers such as wood, cotton, or rayon, or combinationsof natural and synthetic fibers.

The topsheet 24 of the present invention preferably comprises anapertured nonwoven web. Referring to FIG. 2 there is schematicallyillustrated at 100 a process for selectively aperturing a nonwoven websuitable for use as a topsheet on a disposable absorbent article.

According to the present invention, a nonwoven web 102 is unwound from asupply roll 104 and travels in a direction indicated by the arrowsassociated therewith as the supply roll 104 rotates in the directionindicated by the arrows associated therewith. The nonwoven material 102passes through a nip 106 of the web weakening roller arrangement 108formed by rollers 110 and 112.

The nonwoven material 102 may be formed by known nonwoven extrusionprocesses, such as, for example, known meltblowing processes or knownspunbonding processes, and passed directly through the nip 106 withoutfirst being bonded and/or stored on a supply roll.

The nonwoven web 102 may be extensible, elastic, or nonelastic. Thenonwoven web 102 may be a spunbonded web, a meltblown web, or a bondedcarded web. If the nonwoven web is a web of meltblown fibers, it mayinclude meltblown microfibers. The nonwoven web 102 may be made of fiberforming polymers such as, for example, polyolefins. Exemplarypolyolefins include one or more of polypropylene, polyethylene, ethylenecopolymers, propylene copolymers, and butene copolymers.

In another embodiment, the nonwoven web 102 may be a multilayer materialhaving, for example, at least one layer of a spunbonded web joined to atleast one layer of a meltblown web, a bonded carded web, or othersuitable material. For example, the nonwoven web 102 may be a multilayerweb having a first layer of spunbonded polypropylene having a basisweight from about 0.2 to about 8 ounces per square yard, a layer ofmeltblown polypropylene having a basis weight from about 0.2 to about 4ounces per square yard, and a second layer of spunbonded polypropylenehaving a basis weight from about 0.2 to about 8 ounces per square yard.Alternatively, the nonwoven web may be a single layer of material, suchas, for example, a spunbonded web having a basis weight from about 0.2to about 10 ounces per square yard or a meltblown web having a basisweight from about 0.2 to about 8 ounces per square yard.

The nonwoven web may be joined to a polymeric film to form a laminate.Suitable polymeric film materials include but are not limited topolyolefins, such as polyethylenes, polypropylene, ethylene copolymers,propylene copolymers, and butene copolymers; nylon (polyamide);metallocene catalyst-based polymers; cellulose esters; poly (methylmethacrylate); polystyrene; poly (vinyl chloride); polyester;polyurethane; compatible polymers; compatible copolymers; and blends,laminates and/or combinations thereof.

The nonwoven web 102 may also be a composite made up of a mixture of twoor more different fibers or a mixture of fibers and particles. Suchmixtures may be formed by adding fibers and/or particulates to the gasstream in which the meltblown fibers or spunbond fibers are carried sothat an intimate entangled co-mingling of fibers and other materials,e.g., wood pulp, staple fibers and particles occurs prior to collectionof the fibers.

The nonwoven web of fibers should be joined by bonding to form acoherent web structure. Suitable bonding techniques include, but are notlimited to, chemical bonding, thermobonding, such as point calendering,hydroentangling, and needling.

Referring now to FIG. 7 there is shown a photograph of a coherentnonwoven web 102 prior to entering nip 106. As can be seen in FIG. 7 thecoherent nonwoven web comprises a plurality of fibers joined together bypoint calendered bonds 200 to form a coherent web structure.

Referring to FIGS. 2 and 3, the nonwoven web weakening rollerarrangement 108 preferably comprises a patterned calendar roller 110 anda smooth anvil roller 112. One or both of the patterned calendar roller110 and the smooth anvil roller 112 may be heated and the pressurebetween the two rollers may be adjusted by well known means to providethe desired temperature, if any, and pressure to concurrently weaken andmelt-stabilize the nonwoven web 102 at a plurality of locations.

The patterned calendar roller 110 is configured to have a circularcylindrical surface 114, and a plurality of protuberances or patternelements 116 which extend outwardly from surface 114. The protuberances116 are disposed in a predetermined pattern with each protuberance 116being configured and disposed to precipitate a weakened, melt-stabilizedlocation in the nonwoven web 102 to effect a predetermined pattern ofweakened, melt-stabilized locations in the nonwoven web 102. As shown inFIG. 3, patterned calendar roller 110 has a repeating pattern ofprotuberances 116 which extend about the entire circumference of surface114. Alternatively, the protuberances 116 may extend around a portion,or portions of the circumference of surface 114.

The protuberances 116 are preferably truncated conical shapes whichextend radially outwardly from surface 114 and which have ellipticaldistal end surfaces 117. Although it is not intended to thereby limitthe scope of the present invention to protuberances of only thisconfiguration. Other suitable shapes for distal ends 117 include, butare not limited to circular, square, rectangular, etc. The roller 110 isfinished so that all of the end surfaces 117 lie in an imaginary rightcircular cylinder which is coaxial with respect to the axis of rotationof roller 110.

The protuberances 116 are disposed in a regular predetermined pattern ofrows and columns in the embodiment shown in FIG. 3, although it is notintended to thereby limit the scope of the present invention to thepattern of protuberances of only this configuration. The protuberancesmay be disposed in any predetermined pattern about patterned calendarroll 110.

Anvil roller 112, is preferably a smooth surfaced, fight circularcylinder of steel.

FIG. 8 is a photograph of the nonwoven web 102 after having passedthrough the weakening roller arrangement 108, and prior to passingthrough the nip 130 of the incremental stretching system 132. As can beseen in the photograph, the nonwoven web 102 includes a plurality ofweakened, melt-stabilized locations 202. Weakened, melt-stabilizedlocations 202 generally correspond to the pattern of protuberances 116extending from the surface 114 of patterned calendar roller 110. As seenin FIG. 8, the nonwoven web 102 also includes coherent web forming pointcalendered bonds 200 which serve to maintain the structural integrity ofthe nonwoven web 102.

From the weakening roller arrangement 108, the nonwoven web 102 passesthrough nip 130 formed by the incremental stretching system 132employing opposed pressure applicators having three-dimensional surfaceswhich at least to a degree are complementary to one another.

Referring now to FIG. 4, there is shown a fragmentary enlarged view ofthe incremental stretching system 132 comprising incremental stretchingrollers 134 and 136. The incremental stretching roller 134 includes aplurality of teeth 160 and corresponding grooves 161 which extend aboutthe entire circumference of roller 134. Incremental stretching roller136 includes a plurality of teeth 162 and a plurality of correspondinggrooves 163. The teeth 160 on roller 134 intermesh with or engage thegrooves 163 on roller 136, while the teeth 162 on roller 136 intermeshwith or engage the grooves 161 on roller 134. As the nonwoven web 102having weakened, melt-stabilized locations 202 passes through theincremental stretching system 132 the nonwoven web 102 is subjected totensioning in the CD or cross-machine direction causing the nonwoven web102 to be extended in the CD direction. Alternatively, or additionallythe nonwoven web 102 may be tensioned in the MD or machine direction.The tensioning force placed on the nonwoven web 102 is adjusted suchthat it causes the weakened, melt-stabilized locations 202 to rupturecreating a plurality of apertures 204 coincident with the weakenedmelt-stabilized locations 202 in the nonwoven web 102. However, thebonds of the nonwoven web 102 are preferably strong enough such thatthey do not rupture during tensioning, thereby maintaining the nonwovenweb in a coherent condition even as the weakened, melt-stabilizedlocations rupture. However, it may be desirable to have some of thebonds rupture during tensioning.

Referring now to FIG. 9 there is shown a photograph of the nonwoven web102 after having been subjected to the tensioning force applied by theincremental stretching system 132. As can be seen in the photograph, thenonwoven web 102 now includes a plurality of apertures 204 which arecoincident with the weakened, melt-stabilized locations 202 of thenonwoven web shown in FIG. 8. A portion of the circumferential edges ofapertures 204 include remnants 205 of the melt-stabilized locations 202.It is believed that the remnants 205 help to resist further tearing ofthe nonwoven web particularly when the nonwoven web is used as atopsheet on a disposable absorbent article.

Other exemplary structures of incremental stretching mechanisms suitablefor incrementally stretching or tensioning the nonwoven web aredescribed in International Patent Publication No. WO 95/03765, publishedFeb. 9, 1995, in the name of Chappell, et al., the disclosure of whichis incorporated herein by reference.

The selectively apertured nonwoven web may also be used as a topsheet onother disposable absorbent articles such as for example, incontinencebriefs, training pants, feminine hygiene garments and the like. Theselectively apertured nonwoven web may also be used in other portions ofa disposable absorbent article such as, for example, as an acquisitionlayer positioned between the topsheet and the absorbent core, as part ofthe absorbent core, or as portions of other components of the disposableabsorbent article.

The nonwoven web 102 is preferably taken up on wind-up roll 180 andstored. Alternatively, the nonwoven web 102 may be fed directly to aproduction line where it is used to form a topsheet on a disposableabsorbent article.

Referring to FIG. 5 there is schematically illustrated at 300 anotherprocess for selectively aperturing a nonwoven web of the presentinvention. A nonwoven web 302 is unwound from a supply roll 304 andtravels in a direction indicated by the arrows associated therewith asthe supply roll 304 rotates in the direction indicated by the arrowsassociated therewith. The nonwoven material 302 is forwarded through theweb weakening arrangement 308.

The nonwoven material 302 may be formed by known extrusion processes,such as, for example, known melt-blowing processes or known spunbondingprocesses, and passed directly through the web weakening arrangement308.

The nonwoven web 302 may be extensible, elastic or non-elastic. Thenonwoven web 302 may be a spunbonded web, a meltblown web, or a bondedcarded web. If the nonwoven web is a web of meltblown fibers, it mayinclude meltblown microfibers. The nonwoven web 302 may be made of fiberforming polymers such as, for example, polyolefins. Exemplarypolyolefins include one or more of polypropylene, polyethylene, ethylenecopolymers, propylene copolymers, and butene copolymers.

In another embodiment, the nonwoven web 302 may be a multilayer materialhaving, for example, at least one layer of a spunbonded web joined to atleast one layer of a meltblown web, a bonded carded web, or othersuitable material.

The nonwoven web may be joined to a polymeric film to form a laminate.Suitable polymeric film materials include but are not limited topolyolefins, such as polyethylenes, polypropylene, ethylene copolymers,propylene copolymers, and butene copolymers; nylon (polyamide);metallocene catalyst-based polymers; cellulose esters; poly (methylmethacrylate); polystyrene; poly (vinyl chloride); polyester;polyurethane; compatible polymers; compatible copolymers; and blends,laminates and/or combinations thereof.

The nonwoven web 302 may also be a composite made up of a mixture of twoor more different fibers or a mixture of fibers and particles. Suchmixtures may be formed by adding fibers and/or particles to the gasstream in which the meltblown fibers or spunbond fibers are carried sothat an intimate entangled co-mingling of fibers and other materials,e.g., wood pulp, staple fibers and particles occurs prior to collectionof the fibers.

The nonwoven web of fibers should be joined by bonding to form acoherent web structure. Suitable bonding techniques, include, but arenot limited to, chemical bonding, thermobonding, such as pointcalendering, hydroentangling, and needling.

Referring to FIGS. 5 and 6, the nonwoven web weakening arrangement 308preferably comprises an ultrasonic transducer 306 and a cylinder 310. Asthe nonwoven material 302 is forwarded between the ultrasonic transducer306 and the anvil cylinder 310, the nonwoven web 302 is subjected toultrasonic vibrational energy whereupon predetermined pattern locationsof the nonwoven web 302 are weakened and melt-stabilized. Anvil 310 hasa multiplicity of discrete pattern protuberances which are generallydesignated 316 disposed on its outwardly facing surface 314 in apredetermined pattern which extends about the entire circumference ofthe anvil cylinder. The protuberances 316 are disposed in apredetermined pattern with each protuberance 316 being configured anddisposed to precipitate a weakened, melt-stabilized location 304 in thenonwoven web 302 to effect a predetermined pattern of weakened,melt-stabilized locations in the nonwoven web 302. As shown in FIG. 6,anvil 310 has a repeating pattern of protuberances 316 which extendabout the entire circumference of surface 314. Alternatively, theprotuberances 316 may extend around a portion, or portions of thecircumference of surface 314.

The protuberances 316 are preferably truncated conical shapes whichextend radially outward from the surface 314 and which have ellipticaldistal end surfaces. Other suitable shapes for the distal end include,but are not limited to, circular, square, rectangular, etc. The anvil310 is finished so that all of the end surfaces lie in an imaginaryfight circular cylinder which is coaxial with respect to the axis ofrotation of anvil 310.

After having passed through the weakening arrangement 308, and prior topassing through the nip 330 of the incremental stretching system 332,the nonwoven web 302 includes a plurality of weakened, melt-stabilizedlocations 304 which generally correspond to the pattern of protuberances316 extending from the surface 314 of anvil 310.

From the weakening arrangement 308, the nonwoven web 102 passes throughnip 330 formed by the incremental stretching system 332 employingopposed pressure applicators having three-dimensional surfaces which atleast to a degree are complementary to one another. The incrementalstretching system 332 preferably comprises incremental stretchingrollers 334 and 336. The incremental stretching roller 334 includes aplurality of teeth and corresponding grooves which extend about theentire circumference of the roller 334. Incremental stretching roller336 includes a plurality of teeth and a plurality of correspondinggrooves. Teeth on roller 334 intermesh or engage with the grooves onroller 136, while the teeth on roller 336 intermesh with or engage withthe grooves on the roller 334. As the nonwoven web 302 having weakened,melt-stabilized locations 304 passes through the incremental stretchingsystem 332, the nonwoven web is subjected to tensioning causing the webto be extended. The tensioning force placed on the nonwoven web isadjusted such that it causes the weakened, melt-stabilized locations 304to rupture creating a plurality of apertures in the nonwoven web whichare coincident with the weakened melt-stabilized locations.

The nonwoven web 302 is preferably taken up on wind-up roll 380 andstored. Alternatively, the nonwoven web 302 may be fed directly to aproduction line where it is used to form a topsheet on a disposableabsorbent article.

The diaper 20 preferably further comprises elasticized leg cuffs 32 forproviding improved containment of liquids and other body exudates. Eachelasticized leg cuff 32 may comprise several different embodiments forreducing the leakage of body exudates in the leg regions. (The leg cuffcan be and is sometimes also referred to as leg bands, side flaps,barrier cuffs, or elastic cuffs.) U.S. Pat. No. 3,860,003 describes adisposable diaper which provides a contractible leg opening having aside flap and one or more elastic members to provide an elasticized legcuff (gasketing cuff). U.S. Pat. No. 4,909,803 entitled "DisposableAbsorbent Article Having Elasticized Flaps" issued to Aziz et al. onMar. 20, 1990, describes a disposable diaper having "stand-up"elasticized flaps (barrier cuffs) to improve the containment of the legregions. U.S. Pat. No. 4,695,278 entitled "Absorbent Article Having DualCuffs" issued to Lawson on Sep. 22, 1987, describes a disposable diaperhaving dual cuffs including a gasketing cuff and a barrier cuff. U.S.Pat. No. 4,704,115 entitled "Disposable Waist Containment Garment"issued to Buell on Nov. 3, 1987, discloses a disposable diaper orincontinence garment having side-edge-leakage-guard gutters configuredto contain free liquids within the garment. Each of these patents areincorporated herein by reference. While each elasticized leg cuff 32 maybe configured so as to be similar to any of the leg bands, side flaps,barrier cuffs, or elastic cuffs described above, it is preferred thateach elasticized leg cuff 32 comprise at least an inner barrier cuffcomprising a barrier flap and a spacing element such as described in theabove-referenced U.S. Pat. No. 4,909,803. In a preferred embodiment, theelasticized leg cuff 32 additionally comprises an elastic gasketing cuffwith one or more elastic strands, positioned outboard of the barriercuff such as described in the above-referred U.S. Pat. No. 4,695,278.

The diaper 20 preferably further comprises an elasticized waistband 34that provides improved fit and containment. The elasticized waistband 34is that portion or zone of the diaper 20 which is intended toelastically expand and contract to dynamically fit the wearer's waist.The elasticized waistband 34 preferably extends longitudinally outwardlyfrom at least one of the waist edges of the absorbent core 28 andgenerally forms at least a portion of the end edge of the diaper 20.Disposable diapers are generally constructed so as to have twoelasticized waistbands, one positioned in the rear waist region and onepositioned in the front waist region, although diapers can beconstructed with a single elasticized waistband. Further, while theelasticized waistband 34 or any of its constituent elements can comprisea separate element affixed to the diaper 20, the elasticized waistband34 may be constructed as an extension of other elements of the diapersuch as the backsheet 26 or the topsheet 24, preferably both thebacksheet 26 and the topsheet 24. The elasticized waistband 34 may beconstructed in a number of different configurations including thosedescribed in U.S. Pat. No. 4,515,595 entitled "Disposable Diapers withElastically Contractible Waistbands" issued to Kievit et al. on May 7,1985 and the above referenced U.S. Pat. No. 5,151,092 issued to Buell;each of these references being incorporated herein by reference.

In a preferred embodiment, the diaper 20 also comprises elasticized sidepanels 30 disposed in the rear waist region 44. (As used herein, theterm "disposed" is used to mean that an element(s) of the diaper isformed (joined and positioned) in a particular place or position as aunitary structure with other elements of the diaper or as a separateelement joined to another element of the diaper.) The elasticized sidepanels 30 provide an elastically extensible feature that provides a morecomfortable and contouring fit by initially conformably fitting thediaper to the wearer and sustaining this fit throughout the time of wearwell passed when the diaper has been loaded with exudates since theelasticized side panels allow the sides of the diaper to expand andcontract. The elasticized side panels 30 further provide more effectiveapplication of the diaper 20 since even if the diaperer pulls oneelasticized side panel 30 farther than the other during the application(asymmetrically), the diaper 20 will "self-adjust" during wear. Whilethe diaper 20 of the present invention preferably has the elasticizedside panels 30 disposed in the rear waist region 44; alternatively, thediaper 20 may also be provided with elasticized side panels disposed inthe front waist region 46 and the rear waist region 44. While theelasticized side panels 30 may be constructed in a number ofconfigurations, examples of diapers with elasticized side panels aredisclosed in U.S. Pat. No. 4,857,067, entitled "Disposable Diaper HavingShirred Ears" issued to Wood, et al. on Aug. 15, 1989; U.S. Pat. No.4,381,781 issued to Sciaraffa, et al. on May 3, 1983; U.S. Pat. No.4,938,753 issued to Van Gompel, et al. on Jul. 3, 1990; and in U.S. Pat.No. 5,151,092 issued to Buell et al. on Sep. 29, 1992; each of which areincorporated herein by reference. Suitable elastic materials for use asthe elasticized side panels include elastomeric foams, synthetic ornatural rubber, synthetic or natural rubber foams, elastomeric films,elastomeric scrim, elastomeric woven or nonwoven webs, elastomericcomposites such as elastomeric nonwoven laminates, or the like.

The diaper 20 also comprises a fastening system 36 which forms a sideclosure which maintains the rear waist region 44 and the front waistregion 46 in an overlapping configuration such that lateral tensions aremaintained around the circumference of the diaper to maintain the diaperon the wearer. Exemplary fastening systems are disclosed in U.S. Pat.No. 4,869,724 issued to Scripps on Sep. 26, 1989; U.S. Pat. No.4,846,815 issued to Scripps on Jul. 11, 1989; U.S. Pat. No. 4,894,060issued to Nestegard on Jan. 16, 1990; U.S. Pat. No. 4,946,527 issued toBattrell on Aug. 7, 1990; U.S. Pat. No. 3,848,594 issued to Buell onNov. 19, 1974; and U.S. Pat. No. 4,662,875 issued to Hirotsu andRobertson on May 5, 1987. Each of these patents are incorporated hereinby reference.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A method for selectively aperturing a nonwovenweb comprising the steps of:a) providing a nonwoven web; b) weakeningsaid nonwoven web at a plurality of locations to create a plurality ofweakened, melt-stabilized locations; c) providing an incrementalstretching means; and d) subjecting said nonwoven web to incrementalstretching by said incremental stretching means causing said nonwovenweb to rupture at said plurality of weakened, melt-stabilized locationscreating a plurality of apertures in said nonwoven web coincident withsaid plurality of weakened, melt-stabilized locations.
 2. The method ofclaim 1 further comprising selecting said nonwoven web from the groupconsisting of a bonded carded web of fibers, a web of spunbonded fibers,a web of meltblown fibers, and a multilayer material including at leastone of said webs.
 3. The method of claim 2 further comprising includingmeltblown microfibers in said meltblown web.
 4. The method of claim 2further comprising selecting a polymer from said fibers from the groupconsisting of polyolefins, polyesters, and polyamides.
 5. The method ofclaim 4 further comprising selecting said polyolefin from the groupconsisting of one or more of polyethylene, polypropylene, polybutene,ethylene copolymers, propylene copolymers, and butene copolymers.
 6. Themethod of claim 5 further comprising selecting said nonwoven web as acomposite material comprising a mixture of fibers and one or more othermaterials from the group consisting of wood pulp, staple fibers,particulates and superabsorbent materials.
 7. The method of claim 1further comprising providing said nonwoven web as an elastic nonwovenweb.
 8. The method of claim 1 further comprising providing said nonwovenweb as a nonelastic nonwoven web.
 9. The method of claim 1 furthercomprising providing said nonwoven web as an extensible nonwoven web.10. The method of claim 1 further comprising forming said nonwoven webas a laminate with a polymeric film.
 11. The method of claim 1 furthercomprising weakening said nonwoven web in a pattern.
 12. The method ofclaim 1 further comprising weakening said nonwoven web using heat. 13.The method of claim 1 further comprising weakening said nonwoven webusing pressure.
 14. The method of claim 1 wherein said incrementalstretching comprises feeding said nonwoven web through a nip formed by apair of incremental stretching rollers.
 15. The method of claim 14further comprising providing said incremental stretching roller with aplurality of teeth and a plurality of grooves.
 16. A method forselectively aperturing a bonded nonwoven web comprising the steps of:a)providing a nonwoven web; b) weakening said nonwoven web withoutrupturing said nonwoven web at a plurality of locations to create aplurality of weakened, melt-stabilized locations; c) providing anincremental stretching means; and d) subjecting said nonwoven web toincremental stretching by said incremental stretching means causing saidnonwoven web to rupture at said plurality of weakened, melt-stabilizedlocations creating a plurality of apertures in said nonwoven webcoincident with said plurality of weakened, melt-stabilized locations.17. The method of claim 16 wherein said incremental stretching comprisesfeeding said nonwoven web through a nip formed by a pair of incrementalstretching rollers.
 18. The method of claim 17 further comprisingproviding said incremental stretching roller with a plurality of teethand a plurality of grooves.